As working machines, for example forest machines are used, it is known that forest machines include various harvesters, forwarders and combinations of these, which are also called combi machines. In this description, such combi machines are also included when harvesters are referred to, if the function in question is similar to the function in a harvester. It is known that control systems are used for controlling the forest machines. One control system of prior art is Timbermatic 300, which is a system for controlling the functions of a forest machine and particularly a harvester head, and for measuring and bucking timber. In the forest machine, the control system controls, among other things, the diesel motor, the hydrostatic drive transmission, the harvester head, and the boom system, to which the harvester grapple is coupled, as well as all the auxiliary functions related to these. The control system in question operates, for example, in the PC/Windows 2000 operating environment. In the bucking instructions of the control system it is possible to include, for the timber to be processed, for example value, distribution and colour marking matrices, groups of types of timber, and trunk types. By means of an application included in the Timbermatic 300 system, it is possible to analyze and compute the production results, such as the number, length and diameter of logs, their levels of distribution, the groups of types of timber, and the trunk types. A corresponding control system in forwarders is Timbermatic 700, which controls, among other things, time management, positioning, and the loader weigher. A similar control system is also provided for baling presses for logging residues. The display and the central processing unit of the control system are placed in the cabin, within reach for the driver. Normally, the system also comprises a printer.
The control bus in the control and measuring automatics of the control system is based on a CAN bus solution of prior art, in which data is transferred in digital form. In the control bus, measurements and signals are transferred in a way known as such. On the basis of the data, it is possible to monitor measurements relating to the durations and functional speeds of different cycles in the processing. From the signals and measurements, information is obtained about the operating times and timings of components responsible for various functions. The components may be provided, for example, for the functions of the boom system or the harvester head connected to it, such as feeding, diameter measurement, length measurement, sawing, and delimbing. The processing of a single tree trunk involves a large number of measurement values that may be stored in a database which further comprises a classification, for example, on the basis of size classes of trunks and logs. The size class of the log is known on the basis of the measurement values.
Reduced technical performance of a forwarder, a harvester, or a harvester grapple, both in the overall system and its subsystems and constituent functions, will impair the profitability of the harvesting work. It has been difficult to detect a long-term reduction in the performance, because it has been based on, for example, the subjective evaluations and experiences of the operator or the maintenance personnel and servicemen, which may be limited in time and relate to some individual forest machines only. Furthermore, it has been impossible to evaluate effects caused by repair and change works or changes in ways of action in a reliable way.
Document WO 2006/128786 A1 discloses a method and a system for monitoring the function of a subsystem or the performance of one or more functions in a forest machine. It relates to the measurement of the condition or a performance characteristic value of one or more subsystems in a forest machine, and to presenting the result to the driver. Each measurement task involves the filtering of interference data case by case and the processing of data to a reliable characteristic value that can be utilized in the maintenance and optimization of the performance of the machine.
When the driver takes part in the control of the working machine, particularly a forest machine, and in the implementation of the work cycles, the evaluation of the technical performance of the working machine is not unambiguous. The operation of the system is dependent on both the technical performance of the subsystems of the working machine and the skills of the operator, that is, the driver of the forest machine, under varying conditions. The control commands entered by the driver and the driver's way of action will determine the operation of the whole system.
In view of the system for controlling the condition and productivity of the working machine, it is important to monitor and store the duration of each work cycle by taking several samples within a long period of time and then, on the basis of the monitoring, to indicate the changes taking place over a long period of time. Typically, the analysis of the operation and the condition of the working machine is based on statistical data collected over a long period of time.
It is thus necessary to monitor the work cycles of the working machine in real time by using the control commands entered by the driver which can be registered as control signals or messages via the user interface of the machine, as well as by using messages generated by the machine. The commands, messages and signals are transmitted in a control bus where communication can be monitored in real time.
However, the identification of the work cycles of the working machine by means of, for example, communication in the control bus, is a complex task. For identifying the work cycles, mathematical methods (HMM methods) are used, one of which is disclosed in the document “Work cycle recognition in human operated machine using Hidden Markov Models”; Palmroth L. Putkonen A.; The 8th International Conference on Motion and Vibration Control (MOVIC2006); KAIST, Daejeon, Korea; Aug. 27-30, 2006; p. 459-464.
The automatic and continuous identification of work cycles has several advantages relating to the monitoring of the condition and the productivity of the working machine. In the method, the duration of each work cycle and their distribution in time as part of a larger sequence of work cycles or a mode of the working machine, for example the unloading or loading of a forwarder, are monitored and compiled in statistics. By displaying the durations of the work cycles and their mutual distribution in time to the driver via the user interface of the working machine, the driver is given immediate feedback on the condition of the machine and on his own operation. The feedback is useful particularly when history data, such as trend data, are displayed for one or more work cycles, or the driver's performance is compared with, for example, a reference value or the performance of an experienced driver. For example, a reference value is obtained by monitoring other drivers and collecting history data on work cycles.